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Apple G5 Fans run full blast

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#1 ginmasterjedi


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Posted 11 November 2014 - 08:32 PM

I am servicing an Apple G5 Desktop tower computer. The issue is this:

I turn it on and almost immediately the fans kick into full blast.  I force shut it down, unplug EVERYTHING, and it powers up, the apple boot sound sounds off and fans run at normal speed.

I then proceed to plug one peripheral one at a time to find the culprit.

WHEN I plug in the monitor and turn on the computer the fans kick into full blast BUT when I power on the apple WITHOUT the monitor plugged in, it powers up and the apple boot sounds sounds off and the fans run normal. I then proceed to plug in the monitor and almost immediately the fans kick into full blast.


So based on that, is the GRAPHICS card going bad? or is it something more serious like the Logic board or CPU?


Thank you in advance for the replies!

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#2 smax013


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Posted 12 November 2014 - 08:05 PM

Have you tried changing the screen resolution to a lower resolution to see if that changes anything with the fans?


Can you tell if it is the system fan that is running or the graphics card fan?


Last, which version of the Mac OS in the computer running?  Have tried running the Apple Diagnostic/Hardware Test on the computer?  That might help figure out the issue.

#3 ginmasterjedi

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Posted 25 November 2014 - 06:23 PM

So I THINK I found the culprit. I took it all apart, I replaced the Logic board thinking that it would fix it. NOPE! still same issues.  So I took out both CPUs and on one of them on the bottom I saw about 10-15 burned integrated circuits (ICs) and a few around the outside perimeter. I ordered a new one and I have my fingers crossed that it fixes the issue.  Now, do I need any special software to configure the CPUs with new logic board and how do I go about getting that software?


Thank you!

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